Monomorphic premature ventricular contractions in patients without cardiac structural changes: clinical and prognostic significance and evaluation of therapy effectiveness (clinical and experimental study)

Abstract

Aim. To determine the individualized choice of therapy for monomorphic premature ventricular contractions (PVCs) in patients without structural cardiac changes by assessing the predictors of arrhythmogenic cardiomyopathy (ACM) and the clinical and prognostic significance of its course.Material and methods. Experimental study. Animals were used to model PVCs by the mechanism of early post-depolarization (EPD) (aconitine), re-entry (peroxide or H2O2 arrhythmia). In addition to the generally accepted parameters, the following ACMs were analyzed during electrocardiography (ECG): pre-ectopic interval, its variability, maximum index of internal deviation of PVCs, the QRS complex of PVC (QRSpvc), QRS of sinus rhythm (QRSsr), their ratio (QRSpvc/QRSsr), etc. Clinical study. A total of 343 patients with class IV-V PVCs aged 16 to 34 years were observed (B. Rayn, 1984). The same parameters were determined by ECG as in experimental arrhythmias. The follow-up duration was up to 10 years. The end point was the detection or absence of cardiovascular pathology.Results. Experimental study. When modeling ventricular arrhythmias using the EPD mechanism, early (R/T) monotopic PVCs were recorded, and re-entry — early and late monomorphic PVCs. ACM predictors were recorded only when modeling arrhythmia by the re-entry mechanism. Clinical study. In patients without structural cardiac changes, early (R/T) monotopic PVC highly correlated with ventricular ectopy induced by the EPD mechanism (aconitine) (r=0,92). These patients did not have cardiovascular diseases, and the most effective antiarrhythmic drugs for eliminating ventricular ectopy were class I drugs. In patients without structural cardiac changes, early and late monomorphic PVCs highly correlated with experimental ventricular ectopy caused by the re-entry mechanism (H2O2 arrhythmia). In these patients, on average, 7,2±0,5 years after inclusion in the study, various clinical forms of coronary artery disease were detected, and the positive clinical effect of PVC treatment was achieved mainly with the use of class III antiarrhythmic drugs.Conclusion. In patients with early monotopic ventricular ectopia, without detection of ACM predictors, the most effective were class I antiarrhythmic drugs. In other patients with early and late monomorphic ventricular ectopia and detected ACM predictors, class III agents were found to be effective.